The present invention concerns straight oil compositions for fibrous materials. Conventionally, for excellence in heat resistance, lubricity, etc., dimethyl polysiloxane oils have been used widely as straight oils such as spandex oils and sewing machine thread oils. The term "straight oil" means 100% oil treatment agents free from solvent or water.
Recently, for improving smoothness and antistatic properties of dimethyl polysiloxane oils, various improved straight oils have been developed. Examples include mixtures of ethylene oxide- and propylene oxide-based polyoxyalkylene-modified silicones, smoothing agents of viscosity below 100 cSt (centistokes), and higher alcohols, as disclosed in Japanese Kokai Patent No. Sho 48(1973)-19893; mixtures of dimethyl polysiloxane oils of viscosity 3-50 cSt and an alpha.TM.olefin polyether-modified oil as disclosed in Japanese Kokoku Patent No. Sho 53(1978)-81798; mixtures of mineral oil and/or polydiorganosiloxane and amino-modified silicone oil as disclosed in Japanese Kokoku Patent No. Sho 63(1988)-8233; and mixtures of polydimethylsiloxane and polyamylsiloxane as disclosed in Japanese Kokoku Patent No. 42(1967)-8438.
However, conventional oxyalkylene-modified silicones use polyoxyalkylenes that are random copolymers of ethylene oxide and propylene oxide, thus compatibility with the base oil, dimethyl polysiloxane oil is extremely poor, and use of compatibilizers such as higher alcohols and their fatty acid esters is required. However, even with such compatibilizers, there is a limit in solubilizing power. Namely, complete compatibility is not possible, and separation occurs with the elapse of time.
With more of such compatibilizers used, the lubricity of dimethyl polysiloxane oils and the antistatic properties of the polyoxyalkylene-modified silicone oils decrease, thus development of straight oils requiring no compatibilizers is desired.
The amino-modified silicones and amylsiloxanes are not sufficient in antistatic properties, and they yellow fibrous materials.